In the thread twisting industry, one of the most traditional machines that provides the torsion for one or more threads or fibres is the twister and the spinner.
The twisting and rolling or folding process on the reel of these machines is carried out by a rotating spindle system and the ring that guides the runner, the rocker that distributes the thread along the spindle, filling the reel, and the thread feeding. The ratio of the spindle speed to the thread feed speed is constant throughout the reel filling process and corresponds to the theoretical torsion of the programmed thread.
These conventional machines work (amongst others) with some working parameters such as torsions per meter of thread, thread feed speed and spindle revolutions per minute, and fulfills the theoretical expression:Torsions per meter (THEORETICAL)=spindle speed (rpm)/spindle lineal speed (m/min)
This means that in the case of wanting to increase or reduce the spindle lineal speed, the spindle rotation speed increases or reduces by the same proportion, without varying the torsion, for the purpose of keeping constant the theoretical programmed tension value.
Therefore, even though it is known that on these machines the working speeds can be varied during the reel filling for the purpose, amongst others, of reducing the thread breakages, they have always fulfilled this formula and have always changed in the same proportion and at the same time the spindle rotational speed and the thread lineal speed and the (theoretical) torsion per meter value has always been kept constant.
Owing to the imperfect working principle of the system, during this twisting and reel filling process, actually a series of torsion divergences are produced on the thread compared to the programmed theoretical torsion. This means that having a programmed theoretical torsion on the machine, the real torsion on the thread once twisted is always different and variable depending on the portion of thread chosen from the reel.
These torsion variations depend on the runner that moves at a different turning speed to that of the spindle and which is variable throughout the reel filling. Said runner speed depends and is basically related to the spindle speed, the thread feed speed, the speed and the direction (up-down) of the rocker movement and the thread rolling diameter at a specific moment.
This variation of runner speed makes the thread roll onto the reel along the formation of the reel with a real torsions per meter value different to that which is theoretically programmed, as on the conventional machines it is always fulfilled the expression:Torsions per meter (THEORETICAL)=spindle speed (rpm)/thread lineal speed (m/min)
Certainly with this ‘conventional’ working system, actually when the machine operator programmes the torsions per meter of thread to be processed, to a large extent it is unknown that actually the real torsions on the thread will be different to those programmed (theoretical). This ignorance and the ever increasing need to process threads with greater twist quality, less torsion variation, and as a consequence the improved mechanical properties that are the result once having been twisted have brought about the development of this invention.